The Oscar-nominated Singin' in the Rain star was rushed to hospital from her son Todd Fisher's home in Los Angeles, suffering what TMZ reported as a 'medical emergency' and 'possible stroke' earlier on Wednesday (local time).
"She wanted to be with Carrie," Todd told media.
Reynolds had reportedly been distraught ever since she was informed of the heart attack Carrie suffered on December 23.
"Thank you to everyone who has embraced the gifts and talents of my beloved and amazing daughter," Reynolds posted on Facebook on Wednesday, following Carrie's death.
"I am grateful for your thoughts and prayers that are now guiding her to her next stop. Love Carrie's Mother."
A video was posted online of an ambulance leaving Todd's home, where she was said to be discussing funeral plans for Carrie.
Reynolds and Carrie had a famously complicated relationship, widely believed to be reflected in Postcards from the Edge, the 1990 movie based on the semi-autobiographical novel of the same name.
Reynolds was one of Hollywood studio MGM's main stars of the 1950s and '60s. Along with 1952's Singin' in the Rain, she had the lead role in 1964's The Unsinkable Molly Brown, for which she received an Oscar nomination for best actress.
Other notable films she starred in included Three Little Words, The Affairs of Dobie Gillis, Susan Slept Here and The Catered Affair.
In what was to become one of the biggest scandals of the decade, Reynolds' husband and father to Carrie, Eddie Fisher, left her for Elizabeth Taylor in 1958.
Reynolds went on to lead her own TV programme, The Debbie Reynolds Show, and was nominated for Emmys for her roles in A Gift of Love and Will & Grace.
In her later years, she played Liberace's mother in Steven Soderbergh's Behind the Candelabra and frequently did voice work for Kim Possible and Family Guy.
In 2015, she received the SAG lifetime achievement award and was announced as the recipient of the 2016 Academy Awards Jean Hersholt Humanitarian Award.
Mommy's mom is gone now. :( RIP #DebbieReynolds— Carrie Fisher's Dog (@Gary_TheDog) December 29, 2016